The present invention relates to a method and apparatus powered from the suction (i.e., negative pressure) side of a pump for cleaning a water pool; e.g., swimming pool.
The prior art is replete with different types of automatic swimming pool cleaners powered from either the positive pressure side or suction side of a pump. They include water surface cleaning devices which typically float at the water surface and skim floating debris therefrom. The prior art also shows pool wall surface cleaning devices which typically rest at the pool bottom and can be moved along the wall (which term should be understood to include bottom and side portions) for wall cleaning, as by vacuuming and/or sweeping. Some prior art assemblies include both water surface cleaning and wall surface cleaning components tethered together.
The present invention is directed to a method and apparatus driven by water suction (i.e., negative pressure) for cleaning the interior surface of a pool containment wall and/or the upper surface of a water pool contained therein.
Apparatus in accordance with the invention includes (1) an essentially rigid unitary structure, i.e., a cleaner body, capable of being immersed in a water pool and (2) a level control subsystem for selectively moving the body to a position either (1) proximate to the surface of the water pool for water surface cleaning or (2) proximate to the interior surface of the containment wall for wall surface cleaning.
The invention can be embodied in a cleaner body having a weight/buoyancy characteristic to cause it to normally rest either (1) proximate to the pool bottom adjacent to the wall surface (i.e., heavier-than-water) or (2) proximate to the water surface (i.e., lighter-than-water). With the heavier-than-water body, the level control subsystem in an active state produces a vertical force component for lifting the body to proximate to the water surface for operation in a water surface cleaning mode. With the lighter-than-water body, the level control subsystem in an active state produces a vertical force component for causing the body to descend to the wall surface for operation in the wall surface cleaning mode.
A level control subsystem in accordance with the invention can produce the desired vertical force component either by discharging an appropriately directed water outflow from the body, and/or by modifying the body""s weight/buoyancy characteristic, and/or by orientating hydrodynamic surfaces or adjusting the pitch of the body.
Embodiments of the invention preferably also include a propulsion control subsystem for producing a nominally horizontal (relative to the body) force component for moving the body along (1) a path adjacent to the water surface when the body is in the water surface cleaning mode and (2) a path adjacent to the wall surface when the body is in the wall surface cleaning mode. When in the water surface cleaning mode, debris is collected from the water surface, e.g., by skimming. When in the wall surface cleaning mode, debris is collected from the wall surface, e.g., by suction.
Embodiments of the invention are configured to be hydraulically powered from the suction side of an external hydraulic pump typically driven by an electric motor. This external pump generally comprises the normally available main pool pump used for pool water circulation. Proximal and distal ends of a flexible suction hose are respectively coupled to the pump and cleaner body for producing a water flow through the body for powering the aforementioned level control and propulsion subsystems. The hose is preferably configured with portions having a specific gravity  greater than 1.0 so that it typically lies at the bottom of the pool close to the wall surface with the hose distal end being pulled along by the movement of the body.
In preferred embodiments of the invention, the external pump draws a primary pool water inflow through the cleaner body. The primary inflow is used to develop vertical and horizontal force components capable of acting on the body to affect level control and propulsion. A preferred propulsion subsystem is operable in either a normal (i.e., forward) state for moving the body in a first direction, or a redirection (e.g., backup) state for moving the body in a second direction, e.g., laterally and/or rearwardly. Water surface cleaning and wall surface cleaning preferably occur during the forward propulsion state. The redirection state assists the body in freeing itself from obstructions.
The actual motion and orientation of the cleaner body at any instant in time is determined by the net effect of all forces acting on the body. Some of these forces are directly produced by outflows from the cleaner body. Other forces which effect the motion and orientation are attributable, inter alia, to the following:
a. the weight and buoyancy characteristics of the body
b. the hydrodynamic effects resulting from the relative movement between the water and body
c. the drag forces attributable to the suction hose
d. the contact forces of cleaner body parts against the wall surface, and other obstruction surfaces
Preferred embodiments of the invention employ a turbine or other transducer which responds to the primary pool water inflow to drive a flow generator for producing one or more secondary flows. The secondary flows are then utilized to produce vertical and/or horizontal force components which act on the cleaner body for level control and/or propulsion. The flow generator can comprise a propeller or a pump utilizing, for example, a driven paddle wheel. For level control, the secondary flows can (1) be selectively directed by a switchable level flow director to discharge outflows which directly produce a vertical (upward or downward) thrust and/or (2) be used to control the weight/buoyancy characteristic and/or the pitch orientation of the body to enable it to rise or descend. For propulsion, the secondary flows are selectively directed by a switchable propulsion flow director to discharge outflows to produce force components for propulsion in either said first or second directions.
Additionally, the primary and/or secondary flows can be used for control purposes such as for driving a timing assembly to cause the flow directors to switch states.
A preferred cleaner body in accordance with the invention is comprised of a chassis supported on multiple traction wheels; e.g., a front wheel and first and second rear traction wheels. The wheels are mounted for rotation around horizontally oriented axles. The chassis is preferably configured with a nose portion proximate to the front wheel and front shoulders extending rearwardly therefrom. The shoulders taper outwardly from the nose portion to facilitate deflection off obstructions and to minimize drag as the body moves forwardly through the water. Side rails extending rearwardly from the outer ends of the shoulders toward a body tail portion can define chambers for affecting the body""s weight/buoyancy characteristic.
A preferred cleaner body is configured so that, when at rest on a horizontal portion of the wall surface, it exhibits a nose-down, tail-up pitch or attitude. One or more hydrodynamic surfaces on the body creates a vertical force component for maintaining this attitude as the body moves through the water along a wall surface in the wall surface cleaning mode. This attitude facilitates hold down of the wheels against the wall surface and properly orients a vacuum inlet opening relative to the wall surface. When in the water surface cleaning mode, the vertical force component attributable to the hydrodynamic surface is minimized allowing the body to assume a more horizontally oriented attitude. This attitude facilitates movement along the water surface and/or facilitates skimming water from the surface into a debris container.
A preferred cleaner body in accordance with the invention carries a water permeable debris container. In the water surface cleaning mode, water skimmed from the surface flows through the debris container which removes and collects debris therefrom. In the wall surface cleaning mode, water from adjacent to the wall surface is drawn into the vacuum inlet opening and then through the suction hose and debris collector.
A preferred debris container comprises a main bag formed of mesh material containing one or more sheets or flaps configured to readily permit water home debris to flow therepast into the bag but prevent such debris from moving past the sheets in the opposite direction. More specifically, first and second sheets of flexible material are mounted in the bag such that one edge of the first sheet lies proximate to one edge of the second sheet. When the body is moving in its forward direction, pool water flowing into the bag acts to separate the sheet edges to enable debris to move past the edges into the bag. When the body is moving in a direction other than forward, e.g., rearward or laterally, water flow through the bag toward the mouth of the bag acts to close the sheet edges to prevent debris from leaving the bag.
The operating modes of the level control subsystem (i.e., (1) water surface and (2) wall surface) are preferably switched automatically in response to the occurrence of a particular event such as (1) the expiration of a time interval, (2) the cycling of the external pump, or (3) a state change of the propulsion subsystem. The operating states of the propulsion subsystem, i.e., (1) normal or forward and (2) redirection or backup are preferably switched automatically in response to the occurrence of a particular event such as the expiration of a time interval and/or the interruption of forward body motion.
Multiple exemplary embodiments of the invention will be described hereinafter. They are generally characterized by (1) a turbine mounted so as to be driven by the primary inflow and (2) a flow generator driven by the turbine to produce secondary flows. The secondary flows are selectively directed to place the cleaner body proximate to the water surface or wall surface and/or to propel the body therealong.
In a first embodiment using a heavier-than-water body, the level control subsystem in its active state produces a water outflow from the body in a direction having a vertical component sufficient to lift the body to the water surface for water surface cleaning.
In second, third, fourth, fifth, and sixth embodiments, the level control subsystem utilizes one or more hollow chambers carried by the cleaner body for selectively modifying the weight/buoyancy characteristic of the body. More particularly, the subsystem selectively fills the chamber(s) with either (1) air to make the body more buoyant for operation in the water surface cleaning mode or (2) water to increase the body""s weight for operation in the wall surface cleaning mode.
In the second and fifth embodiments (heavier-than-water) (FIG. 11), the level control subsystem in an active state produces a water outflow from the body in a direction having a vertical component for producing lift. Additionally, water is selectively evacuated from a body chamber by an on-board water driven pump to enable outside air to be pulled into the chamber when the body is at the water surface to increase the body""s buoyancy and stability.
In the third embodiment (heavier-than-water) (FIG. 12), a body chamber contains an air bag coupled to an on-board air reservoir. When in a quiescent state, the chamber is water filled and the air bag is collapsed. In order to lift the body to the water surface, suction pulls water out of the chamber enabling the air bag to expand to thus change the body""s weight/buoyancy characteristic and allow it to float to the water surface.
In the fourth embodiment (FIG. 13), the body is configured with at least one chamber which contains a bag filled with air when in its quiescent state. The contained air volume is sufficient to float the body to the water surface. In order to move the body to the wall surface, the level control subsystem in its active state supplies pressurized water to fill the chamber and collapse the bag, pushing the contained air under pressure into an air reservoir.
In a sixth embodiment (FIG. 22, 26) a pitch control subsystem is incorporated to selectively orient the body""s pitch to be either nose (i.e., front) up/tail (i.e., rear) down or nose down/tail up. By selectively orienting the pitch of the body and providing forward propulsion, as from a single jet, the body can be driven either up to the water surface or down to the wall surface. The pitch control subsystem can be implemented by shifting weight and/or buoyancy between the front and rear of the body.
A seventh embodiment (FIG. 29) uses buoyancy modification to float or sink the body. A buoyancy control subsystem is provided including at least one chamber containing a flaccid bag. To float the body, the bag is filled with air provided by a snorkel device. To sink the body, the chamber is filled with water which expels the air from the bag.
In accordance with a useful feature of some embodiments of the invention, one or more traction wheels are driven (e.g., by the primary inflow) to facilitate movement of the body along the wall surface. The periphery of the front wheel can be notched to facilitate it rolling over a hose, e.g., the suction hose, which it may encounter in traversing the pool bottom. Still further, the peripheral surface of the front wheel preferably has a lower coefficient of friction then that of the rear wheels to facilitate the body turning from a straight line travel path.
In accordance with a further feature of some embodiments, a water driven (e.g., by the primary inflow) controller subsystem controls the switching of the level flow director and/or the direction flow director.
Preferably all of the embodiments include a level override control for enabling a user to selectively place the level flow director in either the wall surface cleaning mode or the water surface cleaning mode.
Although multiple specific embodiments of cleaner bodies and level and propulsion control subsystems in accordance with the invention are described herein, it should be recognized that many alternative implementations can be configured in accordance with the invention to satisfy particular operational or cost objectives. For example only, selected features from two or more embodiments may be readily combined to configure a further embodiment.
Among the more significant features is the inclusion of a motion sensor mechanism to sense when the rate of forward motion of the cleaner body diminishes below a certain threshold. This can occur, for example, when the body gets trapped behind an obstruction. By sensing the motion decrease, a redirection state can be initiated to move the body laterally and/or rearwardly to free it of the obstruction. This motion sensing feature has potential application in various types of pool cleaners regardless of whether they operate at both the water surface and wall surface. In accordance with a preferred embodiment, the motion sensor operates in conjunction with a periodic control device, e.g., a direction controller which alternately defines first and second conditions. Redirection is initiated when two conditions occur concurrently; i.e., the periodic control device defining the second condition and the motion sensor indicating that forward motion has diminished below the threshold.
In accordance with a further useful feature, a suction indicator carried by the body is preferably coupled to the water distribution system to indicate to a user whether the magnitude of negative pressure being delivered to the body is within an acceptable operating range.